Patent Document 1, for example, describes that, because an engine equipped with an exhaust supercharger (a turbo) becomes unable to perform prompt acceleration if a transient state occurs in a period until an exhaust gas amount increases, increasing number of rotations of the supercharger after an accelerator pedal is stepped on, generating so-called turbo lag, to detect such turbo lag and perform prompt acceleration in accordance with a stepped-on state of the accelerator pedal, a shift-down signal is output from an equipped control means, and an automatic transmission shifts down to cause output torque to increase.